Plug and cylinder type lock mechanism



J. W. TAYLOR PLUG AND CYLINDER TYPE LOCK MECHANISM Jan. 3, 1956 Filed Feb. 18, 1952 INENTOR JAC K W- TA L 0/? ATTORNEY United States Patent Ofifice 2,729,092 Patented Jan. 3, 1956 2,729,092 PLUG AND CYLINDER TYPE LUCK MECHANISM Jack William Taylor, New Denham, England, assigncr to Ingersoll Limited, London, England Application February 18, 1952, Serial No. 271,991

Claims priority, application Great Britain February 19, 1951 6 Claims. (Cl. 70-364) This invention relates to plug and cylinder type lock mechanism intended for association with or forming part of a lock, such mechanism including a cylinder and key receiving plug mounted for rotation therein through the medium of an inserted key, the plug being normally locked against rotary movement, but unlocked as a result of insertion of the correct key to permit rotation of the plug and consequential withdrawal of the bolt of the lock.

A plug and cylinder type lock mechanism in accordance with the present invention comprises a fixed cylinder, a key receiving plug mounted for rotational or part rotational movement therein under the action of the appropriate key, a series of tumblers mounted in said plug for individual sliding movement in an arcuate path as a result of the lift imparted to said levers by serrations or notches on the edge or edges of an inserted key and a talon or other means for normally preventing rotation of said plug within said cylinder and movable or being otherwise rendered inoperaitve as a result of insertion of the correct key in the key slot in said plug.

The talon, if such is provided may engage a recess in the inner wall of the cylinder and co-operates with notches in the tumblers which notches are normally misaligned and consequently maintain the talon in engagement with the recess, but on being aligned as a result of the entry of the appropriate key allow the talon to enter the aligned notches and move clear of the recess in the cylinder, thus permitting of rotational movement of the plug within said cylinder under the control of the inserted key.

Alternatively the tumblers may be provided with projections which normally enter recesses formed in the walls of the cylinder, but which are moved out of engagement therewith as a result of the tumblers having the correct lift imparted to them by the insertion of the appropriate key into the key slot.

In order that the invention may be clearly understood and readily carried into effect the invention is hereinafter described with reference to the accompanying drawings in which:

Figures 1 to 5 of the accompanying drawings illustrate the invention applied to a plug and cylinder lock mechanism incorporating a pivoted talon.

Figures 6 to 9 illustrate the invention applied to a plug and cylinder lock mechanism, wherein the tumblers are formed with projections which take the place of a talon.

Figure 10 is a longitudinal section through the plug and cylinder showing a key inserted in position therein.

Figure 11 is a cross section of a portion of the cylinder showing the talon and the spring for moving the talon out of engagement with the notchees.

Referring in the first case to Figures 1 to 5 of the accompanying drawings, the lock mechanism comprises a cylinder 1 containing a plug 2, the latter being formed with a series of axially spaced arcuate shaped compartments 3 in each of which is slidably mounted an arcuate shaped tumbler 4, each tumbler 4 being in the form of a sheet metal stamping and describing an arcuate path of movement, the mythical centre of the are being disposed outside the periphery of the plug.

Each tumbler is normally held in the position shown in Figures 1 and 2 by an associated blade spring 5 which is anchored to the plug at a convenient point and it will be appreciated that as the key 6 (Figure 10) is notched or serrated on both edges there will be two sets of tumblers which will be lifted in opposite directions as a result of the insertion of the key into the key slot 7 which is formed in the plug. The position taken up by one tumbler of each set is shown in Figures 1 and 2.

It will be seen that each tumbler is notched as at 8 on its periphery and normally these notches will all be misaligned, the tumblers being produced as metal stampings in sets which can be assembled together to give a particular combination. Each tumbler is formed with a centre opening 9 for the passage of the key therethrough and the serrated or notched edge of the key will engage the inner edge of this opening as at 10. In Figures 1 to 5 the invention is shown applied to lock mechanism as disclosed in application Serial No. 271,992, filed concurrently herewith in which the plug is formed with two key slots 7 and 7, one of which is enterable from the front of the plug and the other is enterable from the back and consequently the edge 10 of the opening will be of the stepped formation shown so that the correct lift will be imparted to the tumblers irrespective of the direction of key entry. It must be clearly understood, however, that the invention is equally applicable to the more simple type of plug which is provided with a single key slot enterable from the front end of the plug only.

The plug carries a pivotally mounted talon 11 which normally enters a recess 12 in the inner surface of the cylinder and as a result of the fact that the notches 8 are normally misaligned is prevented from entering the notches and consequently by virtue of its engagement with the recess 12 prevents rotational movement of the plug within the cylinder unless the appropriate key has been inserted into the key slot, that is to say, a key which is so serrated or notched as to impart the requisite lift to all the tumblers to bring all the notches 8 into alignment.

In Figures 3 to 5 the correct key 6 has been inserted in the key slot bringing the notches 8 into alignment and the talon is free to move out of the recess 12 and into the aligned notches. Entry of the talon into the aligned notches results from initial turning movement of the key and the plug in the cylinder, the talon as a result of its engagement with the curved or inclined edges of the recess 12 being cammed out of the recess and into engagement with the notches in the tumblers, the plug being then free to be turned through 360 to actuate the lock. On the plug returning to its initial position, that is to say, after the lock has been actuated the talon will again be free to enter the recess 12, that is to say, to move clear of the notches 8 and thus permit withdrawal of the key. For this purpose, as shown in Figure 11 a spring 16 may be associated with the talon which will tend to move the talon out of engagement with the notches and into the recess, or alternatively the talon may be moved by the cam arrangement shown in Patent No. 2,524,339 granted to R. W. Young and myself on October 3, 1950.

In Figures 6 to 9 an alternative form of tumbler is illustrated with which construction it is not necessary to utilize a talon for preventing rotational movement of the plug 2 within its associated cylinder 1. In this construction each tumbler 4 is provided with two oppositely to he lifted in opposite directions as a result of insertion of the key into the key slot 7, the projections 13 are shown in engagement with their adjacent recess 14 and consequently it is not possible to rotate the plug 2' within the cylinder 1 and thus actuate the lock. On the appropriate key 6 being inserted into thekey slot the tumblers 4 will be lifted in opposite directions the correct amount to free the projections 13 and 13a from the respective recesses 14 and thus permit the plug to beturned within the cylinder under the control of the inserted key and to thereby actuate the lock mechanism.

It is desirable to use two oppositely disposed projections, as is clearly shown in the drawings, from the point of view of ensuring that the key mechanism shall not be actuated unless the correct key is inserted. It will be appreciated that a key having, for example, a greaterlift than normally might result in the projections 13 being moved clear of their recesses 14, but it would also result in the oppositely disposed projections 13a entering the opposite recess and consequently although one projection had been moved clear of its recess the other projection would be moved into its adjacent recess, thus preventing the plug being turned. It will be appreciated therefore that by providing two such projections it is absolutely essential for the correct lift to be imparted to the tumblers to free the plug, that is to say, the lift must be no more or no less than that for which the tumbler was designed.

It is preferred to form the projections of the curved formation shown, whilst the recesses 14 are correspondingly shaped in cross section, that is to say, they are more or less of a dovetailed form so that there will be a tendency for the projections to dig into the recesses if an attempt were made to turn the plug in the cylinder with the incorrect key or some form of instrument inserted in the key slot and irrespective of the direction of turning movement.

As in the case of Figures 1 to 5 the tumblers are normally held in the position shown in Figures 6 and 7 by associated blade springs 5' which blade springs return the tumblers to the'position shown as the key is withdrawn from the slot.

In Figures 6 to 8 the plug is formed with a single key slot 7 whereas in Figure 9 two slots 7 and 7 are provided which are laterally spaced and which are enterable respectively from the front and rear of the plug, the key engaging part 10 of the tumbler being of the stepped formation and described in connection with the previously described construction.

The general disposition of the compartments in the plug is clearly shown in Figure 10 and the staggered arrangement of the tumblers, this arrangement being common to both the constructions shown by Figures 1 to 5 and the construction shown by Figures 6 to 9. The plug may be of a fabricated construction in which case it will be built up of suitable spacing members providing intermediately arranged compartments in each of which is mounted a tumbler or it may be produced by a machining operation or in the form of a die-casting.

Although in all the constructions shown the tumblers are urged in one direction by springs of the blade type it must be clearly understood that springs of other type, such as spiral springs or springs of the helical compression type may equally well be employed.

I claim:

1. Plug and cylinder type lock mechanism comprising a fixed cylinder, a key receiving plug mounted for rotational movement within said cylinder under the turning action of an inserted key, said plug having a plurality of arcuate shaped compartments, a series of arcuate shaped tumblers mounted in said arcuate shaped compartments for individual sliding movement through an arcuate path in said plug as a result of their engagement by an inserted key, and means controlled by said tumblers for preventing rotational movement of said plug within said cylinder until all the tumblers have been lifted the correct amount as a result of the insertion of the correct key into the plug.

2. Plug and cylinder type lock mechanism as claimed in claim 1 wherein said means comprises projections on said tumblers which normally enter a recess formed in the wall of said cylinder but are moved out of said recess to permit rotation of said plug as a result of said tumblers being given the correct individual lift consequent upon the insertion of the correct key, said projections and recess being of dovetail shape so that unauthorized rotational movement of said plug will increase the depth of entry of said projections in said recess.

3. Plug and cylinder type lock mechanism as claimed in claim 2, wherein the tumblers are formed with two oppositely directed projections which co-operate with two recesses in said cylinder, whereby both projections are freed from both recesses only on the correct lift being imparted to each individual tumbler and unauthorized angular movement of the plug in the cylinder in either direction will tend to increase the depth of entry of the projections into their recesses.

4. Plug and cylinder type lock mechanism as claimed in claim 1 wherein said means comprises a talon carried by said plug and normally engaging a recess in the inner wall of said cylinder and movable as a result of permitted angular movement of said plug out of said recess into a series of notches formed in the periphery of said tumblers when said notches are aligned as a result of said tumblers being all given the correct individual lift.

5. Plug and cylinder type lock mechanism as claimed in claim 1, wherein the arcs of said compartments and tumblers have a radius on a center beyond said plug.

6. Plug and cylinder type lock mechanism as claimed in claim 1, wherein each tumbler is formed with a central opening for the passage of the key therethrough, the notched key edge engaging the tumbler edge bordering each opening, said plug comprising two key slots enterable one from the front and the other from the rear of the plug, said key slots being laterally spaced, the key engaging edge of the opening in each tumbler being of stepped formation to ensure each tumbler being given the correct lift irrespective of the direction of entry of the inserted key.

References Cited in the file of this patent UNITED STATES PATENTS 408,147 Taylor July 30, 1899 1,964,963 Shinn July 3, 1934 2,139,8 2 Miller Dec. 13, 1938 2,206,539 Swanson July 2, 1940 2,460,551 Swanson Feb. 1, 1949 2,524,339 Young et al Oct. 3, 1950 FOREIGN PATENTS 153,145 Austria Apr. 11, 1938 529,771 Germany July 16, 1931 982,349 France Jan. 24, 1951 993,764 France July 25, 1951 

